Pulverulent mixture for tanning raw animal hides and leather

ABSTRACT

A PULVERULENT MIXTURE FOR TANNING HIDES AND LEATHER COMPRISING (A) A CHROME TANNING AGENT, (B) A PRODUCT OF THE CHLORONATION OF PARAFFIN HYDROCARBONS OF ABOUT 8-24 CARBON ATOMS AND HAVING A CHLORINE CONTENT OF ABOUT 2050% BY WEIGHT, AND (C) AN ADDUCT OF ABOUT 20 TO 70 MOLES OF ETHYLENE OXIDE TO ONE MOLE OF AN ALKYLPHENOL, ARYLALKYLPHENYL OR FATTY ALCOHOL. THE MIXTURE DISPRESS READILY IN WATER TO FORM STABLE TANNING EMULSIONS WHICH YIELD LEATHERS CHARACTERIZEDBY SOFTNESS, SMOOTHNESS AND SUPERIOR GRAIN CHARACTERISTICS.

United States Patent US. Cl. 8 -9426 5 Claims ABSTRACT OF THE DISCLOSURE A pulverulent mixture for tanning hides and leather comprising (a) a chrome tanning agent, (b) a product of the chlorination of paraffin hydrocarbons of about 8-24 carbon atoms and having a chlorine content of about 20- 50% by weight, and (c) an adduct of about 20 to 70 moles of ethylene oxide to one mole of an alkylphenol, arylalkylphenyl or fatty alcohol. The mixture dispersesreadily in water to form stable tanning emulsions which yield leathers characterized by softness, smoothness and superior grain characteristics.

The present invention relates to a new tanning mixture for animal hides and leather, to its production, and to its use.

Chlorinated parafiins in the form of aqueous emulsions have already been used in chrome tanning. In these known processes, however, the aqueous emulsion of the chlorinated hydrocarbons was first manufactured and was added to the tanning bath separately from the tanning material,

, before or during the chrome tanning. Apart from the fact that these processes are complex, they display the disadvantage that because of the differences in batches of the chlorinated parafiin emulsions, caused by temperature and time factors during the manufacture of the emulsions and especially during the compounding of the emulsions, variations occurred in how the individual tanning batches turned out.

It is accordingly an object of the'invention to provide tanning emulsions which produce uniform tanning results.

A further object of the invention is to provide a composition which can readily be formed into a tanning emulsion giving leathers characterized by softness and smoothness.

These and other objects and advantages are realized in accordance with the present invention pursuant to which there is provided a pulverulent mixture for tanning animal hides and leather, the mixture comprising (a) a chrome tanning agent; (b) a chlorination product of parafiin hydrocarbons of about 8-24 carbon atoms and having a chlorine content of about 20-50% by weight; and (c) an adduct of about 20 to 70 moles of ethylene oxide 'with an alkylphenol, aralkylphenol or fatty alcohol.

The mixture comprises preferably (a) 100 parts by weight of the chrome tanning agent; (b) 5-25 parts by weight, optionally 10-20 parts by weight of the said chlorination product; and (0) 1-15 parts by weight, optionally 2-5 parts by weight of the said adduct.

The invention also provides an advantageous method of producing the tanning mixture of the invention comprising mixing the chlorination product and the-adduct to form an intermediate mixture, and then admixing the chrome tanning agent with the said intermediate mixture.

The chrome tanning agents used in the mixtures accordnonylphenol-polyglycol-ether, warmed to 3,826,610 Patented July 30, 1974 'As component (0) of the-mixtures according tothe invention" there may especially be mentioned the adducts of about 20 to moles of ethylene oxide to higher (O -C alkylphenols such'as nonylphenol, dodecylphenoland hexadecylphenol, to aralkylphenols, such as phenol, C -C -alkylphenols, oand p-hydroxydiphenyl substitutedby benzyl, methylbenzyl, dimethylbenzyl, methylbenzyl or p-phenylethyl radicals, e.g. di-benzylphenol or the reaction product of o-hydroxydiphenyl with 1-3 moles of styrene or higher (C C2 fatty alcohols, such as lauryl alcohol, stearyl alcohol and oleyl alcohol. In the adducts, a small percentage of the ethylene oxide, say up to about 5% by weight, can be replaced by propylene oxide. nI the tanning mixtures of the invention these adducts function as non-ionic emulsifiers.

In some cases it has proved advantageous to employ anionic auxiliaries (emulsifier), such as paraflinsulfonic acids, especially alkylbenzenesulfonic acids, for example dodecylbenzenesulfonic acid, or their salts, additionally to the non-ionic emulsifiers in the mixtures according to the invention. The ratio of the amounts of anionic auxiliaries to the amounts of non-ionic emulsifiers is appropriately 1:l-10.

The use of the tanning mixtures according to the invention provides a simplified procedure and results in tanning batches of constant quality being obtained. The chrome leathers obtainable by means of' the tanning mixtures according to the invention are distinguished by outstanding properties, especially by very soft handle, excellent smoothness and superior grain characteristics. Furthermore, the chrome leathers manufactures in this way give particularly good evenness during subsequent aniline dyeing. Apart from the tanning, uniform fat liquoring over the entire cross-section of the leather, and optimum distribution of the natural grease of the hides to be tanned is achieved.

It was surprising that it is possible to manufacture, from chrome tanning materials and chlorinated parafiins pulverulent mixtures which on simple addition in the undissolved form to tanning liquors give stable tanning emulsions, because it would have been expected that as a result of the extremely high electrolyte concentrations which occur when dispersing these mixtures in water no stable emulsions would be produced, but rather that the high salt content would cause the chlorinated paratfins to separate out immediately. Only through the conjoint use of the special highly ethoxylated emulsifiers are mixtures obtained which yield stable emulsions despite the high electrolyte content.

The parts indicated in the Examples which follow are parts by weight:

EXAMPLE 1 100 parts of pulverulent chromium-III sulfate (Cr O content: 26%; content: 27%; Na SO content: 23%) are. mixed with 20 parts of sodium bicarbonate. This mixture is subsequently treated with a mixture. of 15 parts of n-chlorinated paraffin (C -C -parafiin; chlorine content 35%) and 3 parts .of an adduct of 30 moles of ethylene oxide to 1 mole of nonylphenoh'produced by stirring the 60 C., into the chlorinated parafiin. e

The resulting mixture is outstandingly suitable for the manufacture of soft side leather (grained upper leather,

suede leather and nubuck).

parts of cow pelts are pickled with sodium chloride and sulfuric acidiin a tanning vat inthe usual m anner.;12

parts of the tanning mixture described above are added to the pickle. The time in the tanning vat is 8 hours, the initial temperature 20 C. and the final temperature 40 C. The leathers are subsequently neutralized, dyed and fat liquored in the usual manner, the amount of grease being .reducedby Theitinished-leatherssare very soft and very supple and can be dyed very evenly with aniline dyes.

Side leathers of the same quality were also obtained if insteadpf'the indicated tanning mixture the same amount of, one ofthe tanning mixtures A or B described below was employed.

' Tanning Mixture A 100 parts of pulverulent chromium-(III) sulfate (Cr O 3 'content: 26%; S content: 127% Na SO content 23%) are mixed with 8 parts of ground dolomite and 14 parts Tanning Mixture B 100 parts of chromium-(III) sulfate containing formate groups (Cr O content: 28%; S0 content: 13%; formic acid content: Na SO content: 30%) and a mixture of parts of n-chlorinated parafiin (C C -parafiin; chlorine content: 38%) and 3 parts of an adduct of 50 moles of ethylene oxide to oleyl alcohol, which was prepared by stirring the oleyl alcohol-polyglycol-ether, warmed to 60 G, into the chlorinated parafiin, are brought together.

EXAMPLE 2 100 parts of pulverulent chromium-(III) sulfate (Cr O content: 26%; S0 content: 27%;Na SO content: 23%) are treated with a mixture of 14 parts of n-chlorinated .parafiln (C -C -paraffin; chlorine content: 42%) and 6 parts of an adduct of 40 moles of ethylene oxide to 1 mole of di-(phenylethyl)-phenol, which was prepared by stirring the di (phenylethyl)-phenol-polyglycol-ether,

I warmed to 60 C., into the chlorinated parafiin.

The resulting mixture is outstandingly suitable for the production of napa side leather.

100 parts of cow pelts are pickled with sodium chloride and sulfuric acid in a tanning vat in the usual manner. 10 parts of the tanning mixture described above are added to the pickle at C. After minutes time in the tanning vat, 1.5 parts of sodium carbonate (dissolved 1:10 in water) are continuously added over the course of 30 minutes. The total time in the tanning vat is 8 hours and the final temperature 35 C. The leathers are subsequently neutralized, dyed and greased in the usual manner, the greasing being reduced by 25%. The finished leathers are very soft and show a very even aniline dyeing.

EXAMPLE 3 100 parts of pulverulent chromium-(III) sulfate (Cr O content: 26%; S0 content: 27%; Na- SO content: 23%) are mixed with 15 parts of sodium sulfite. This mixture is subsequently treated with a mixture of 12 parts of n- ".chlorinated paraflin ,C C -paraifin; chlorine content: 22%) and 4 parts of an adduct'o'f 20 moles of ethylene oxide to 1 mole of dodecylphenol, which was prepared 1 by stirring the dodecylphenol-polyglycol-ether, warmed to 60 G, into the chlorinated paraffin; 1

1 The resultantmixture is outstandingly'snitable for the manufacture of suede calf.

100 parts of calf hides which have been chrome-tanned and "shaved in" the conventional manner arere-ta'nned in 100 parts of water with 6 parts of. the tanning mixture ...described. above, for ,1 hour at. 40 inya tanning vat.

The leathers are further processed into suede in the usual manner, with or without intermediate drying before dyeing. The resulting leathers are distinguished by a very uniform color and a velvety sheen.

EXAMPLE 4 parts of pulverulent chromium-(III) sulfate'-(Cr O content: 26%; S0 content: 27%; Na SO content: 23%) are mixed with 15 parts of sodium carbonate in 20 parts of sodium forfnate. This mixture is subsequently treated with a mixture of 16 parts of n-chlorinated paraffin (C -C -paratfin; chlorine content: 40%) and 4 parts of an adduct of 60 moles of ethylene oxide to one mole of di-(phenylethyl)-phenol, which was prepared by stirring the di-(phenylethyl)-phenol-polyglycol-ether, warmed to 60 G, into the chlorinated parafiin.

The resulting mixture is outstandingly suitable for the re-tanning of napa leather.

100 parts of side leather which has been chrome-tanned and shaved in the conventional manner are re-tanned in 100 parts of water with 8 parts of the tanning mixture described above, for 1 hour at 40 C. ina tanning vat. The leathers are further processed in the usual manner for napa side leather. The resulting leathers are very soft and very supple and are dyed very uniformly by aniline dyes.

It will be appreciated that the instant specification and examples are set forth by way of illustration and not limitation and that various modifications and changes may be made without departing from the spirit and scope of the present invention.

What is claimed is:

1. A pulverulent mixture for tanning raw hides and leather comprising by weight (a) about 100 parts of a chrome tanning agent; (b) about 5 to'25 parts of a chlorination product of paraffin hydrocarbons of 8-24 carbon atoms and having a chlorine content of about 20-50% by weight; and (0) about 1,to 15 parts of an adduct of about 20-70 moles of ethylene oxide to one mole of an alkylphenol, aralkylphenol or fatty alcohol.

2. The mixture of claim 1 wherein the components (a), (b) and (c) are employed in a weight ratio of about 100:1020:25.

3. The mixture of claim 1 wherein up to 5% by weight of ethylene oxide is replaced bypropylene oxide.

4. The mixture of claim 1 containing also an anionic emulsifier in a weight ratio of between 1 to 1 and 1m 10 based on the said adduct.

5. In the tanning of animal hides wherein the hides are immersed in a pickling bath, treated with a chromiumcontaining tanning agent, the improvement which comprises adding said tanning agent to said bath in the form of a pulverulent mixture comprising (a) a chrome tanning agent; (b) a product of the chlorination of paraffin hydrocarbons of 824 carbon atoms and having a chlorine content of about 20-50% by weight, and v(c) an adduct of about 20-70 moles of ethylene oxide with an alkylphenol, aralkylphenol or fatty alcohol, the components (a), (b)) and (c) being employed in a weight ratio of about 10025-25 :1-15.

No references cited LEON D. RO'SDOL, Primary Examiner I H. WOLMAN, Assistant Examiner US. 01. X.R. 

